I think “fail fast” and “fail early” are redundant; my preferred three fails (with a bad taste of non-grammatical in my mouth) have been “fail fast, fail safe, and fail cheap.” Fast makes natural sense; prolonged failure is clearly unappetizing. Safe is crucial, too: let’s make sure no one gets hurt physically or (too) emotionally. And cheap is a good way to preserve your gig if you are testing things at work. Even the most inspired boss will have a hard time accepting a $1M failure, regardless of whether your resignation accompanies the news.